1. Field of the Invention
The present invention relates to an interference check system that checks interference between a machine tool and a robot in real time.
2. Description of the Related Art
At present, a CAD/CAM system for creating a machining program of a machine tool is commonly used. For example, JP H07-050407 B has described the technique in which a CAD/CAM system and a machine tool are connected on-line, detection data of the position and speed of an object to be controlled based on a clock signal that is detected on the machine tool side is caused to be fed back to the CAD/CAM and comparison operation processing of the detection data and NC data is performed, and correction control is performed by a closed loop that corrects the NC data.
JP 2012-060207 A has described a communication/control system in which a communication controller and a plurality of controllers each having an actuator and operating an object to be controlled are connected via a network.
WO 2010/095713 A describes a wireless communication system and a wireless communication method for causing a plurality of devices to perform a collaborative work at fixed intervals.
JP 2009-020547 A describes a distributed motion control system in which a control instruction with no absolute time attached is transmitted from a controller by an asynchronous communication method and thus a plurality of motors is controlled in synchronization.
Further, JP 2010-218036 A describes an off-line programming device having a second communication module that is connected with a first communication module of an NC simulator via a communication circuit and performs communication of information with the first communication module, a robot simulator that performs a simulation of a robot based on the information, and a program generation device that generates a teaching program off-line by using the simulation results in the robot simulator.
In the case where a robot is controlled by using some simultaneous axes control function of CNC of a machine tool, such as the FANUC Multi-path Control for the paths of the turning or the milling and the paths of a loader control path, it is possible to check interference in real time between the robot and the machine tool by using the CAD/CAM system as described in JP H07-050407 B. However, conventionally, in the case where the robot is not controlled directly by the CNC of the machine tool, the interlock between the robot and the machine tool by an I/O signal so that interference is prevented from occurring when the machine tool and the robot are caused to perform a collaborative work. It is known that a robot has a processing unit, inside the controller, configured to perform a real-time interference check, and there is a function that immediately takes steps in the case where the robot and another object are going to interfere with each other.
Except for the case where a robot is controlled by using the simultaneous axes control function of the CNC of the machine tool, there is such a problem that the machine tool and the robot are caused to perform a collaborative work because the real time interference check CAD/CAM system connected the CNC cannot check interference with the robot and the machine tool.
Even though both a machine tool and a robot have some physical connection interface ports suitable to communication with the real-time interference check CAD/CAM system, there is a case where the number of connection ports is actually insufficient when an attempt is made to connect the real-time interference check CAD/CAM system to one device and to further connect it to another device. Even if there is a communication connection port available at both the machine tool and the robot, there is a case where the specifications lack the real-time communication properties. In this case, the real-time interference check CAD/CAM system needs to combine the data, that is transmitted from one device, with the other data, that is transmitted from the other device. Furthermore the real-time interference check CAD/CAM system must correct the other data, that is transmitted from the other device, with respect to time. But there is such a problem that means the CAD/CAM system has no function of the correction are not available.
Further, even in the case where the robot itself has the real-time interference check function, there is such a problem that means for taking in the control-path of the mechanical unit of the machine tool in real time on the robot coordinate system and for checking interference between the mechanical unit and the robot and between the mechanical unit and the peripheral are not available.
None of the inventions described in the above-described patent documents will solve the above-described problems. For example, the invention described in JP 2012-060207 A is recognized as one relating to a motion control communication system for controlling a plurality of mechanical units (controllers) by one communication controller, but this invention premises that the real-time properties of the communication between the communication controller and each controller are secured, and therefore, in the case where the real-time properties are not secured, it is recognized that appropriate measures cannot be taken.
WO 2010/095713 A describes a technique for implementing motion control of slave stations, such as a robot and a servomotor, from a master station by wireless communication, but has not referred to the case where different kinds of communication protocols exist in the communication system.
JP 2009-020547 A has described that it is possible to synchronously control a group of servomotors by mounting a non-real-time OS and by using a general-purpose personal computer including the IEEE1394 interface. However, the object of the invention described in JP 2009-020547 A is the motion control, which is different from the interference check of the present invention.
Further, JP 2010-218036 A has described that information for checking interference is displayed on a monitor, but an operator actually checks interference, and there is not description of checking interference in real time by some automated system.